Image sensor, imaging apparatus and live body imaging apparatus

ABSTRACT

An image sensor including a pixel unit, the pixel unit including a photodiode, a first color filter and a second color filter each disposed in a different position on a plane above the photodiode, and a first on-chip lens disposed over the first color filter and a second on-chip lens disposed over the second color filter.

BACKGROUND

The present technology relates to an image sensor, an imaging apparatusand a live body imaging apparatus, in particular to an image sensorwhich is capable of creating optimal spectral characteristic, an imagingapparatus and a live body imaging apparatus.

In a known image sensor such as CMOS (Complementary Metal OxideSemiconductor) image sensor, generally, a pixel is configured including,with respect to a single photodiode, a single color filter and a singleon-chip lens are disposed (refer to, for example, Japanese UnexaminedPatent Application Publication No. 2010-232595). On the other hand,there is another known pixel is configured including, for example, withrespect to plural photodiodes, a single color filter is disposed, andoutputs from the plural photodiodes are added (refer to, for example,Japanese Unexamined Patent Application Publication No. 2010-28423).

SUMMARY

However, in the pixels which have a configuration taught by JapaneseUnexamined Patent Application Publications No. 2010-232595 and JapaneseUnexamined Patent Application Publication No. 2010-28423, the spectralcharacteristic of the light concentrated on the photodiode depends onthe spectral characteristic of the color filter disposed above thephotodiode. Therefore, in order to improve the S/N ratio (Signal toNoise Ratio) and the color reproducibility, development of a new colorfilter is desired. However, for developing a new color filter, enormoustime and cost is necessary. Also, even when a material for new colorfilter is developed, it is difficult to obtain optimal spectralcharacteristic of the light concentrated on the photodiodes of therespective pixels suitable for the application. Under suchcircumstances, a technique to create optimal spectral characteristic,which does not depend on only the development of material for colorfilter, is desired.

The present technology has been proposed in view of the abovecircumstances to create an optimal spectral characteristic.

An image sensor an aspect of the present technology includes a pixelunit, which has a photodiode; a first color filter and a second colorfilter each disposed in a different position on a plane above thephotodiode; and a first on-chip lens disposed over the first colorfilter and a second on-chip lens disposed over the second color filter.

Each of the first color filter and the second color filter may have aspectral characteristic different from each other.

The pixel unit may output an electrical signal of a level correspondingto a composition result of the spectral characteristics of the firstcolor filter and the second color filter.

The photodiode may include a first photodiode disposed below the firstcolor filter and a second photodiode disposed below the second colorfilter, and electrical signals output from the pixel unit having levelscorresponding to the respective spectral characteristics of the firstcolor filter and the second color filter may be added.

The pixel unit may further include a common floating diffusion that addselectrical signals output from each of the first photodiode and thesecond photodiode.

Each of the electrical signals output from the first photodiode and thesecond photodiode may be amplified by an individually preset gain.

Each of the first photodiode and the second photodiode may beindividually preset with a charge accumulating time.

Each of the first color filter and the second color filter may have acharacteristic to transmit infrared light.

The pixel unit may include a group of color filters which includes oneor more color filters in addition to the first color filter and thesecond color filter, and a group of on-chip lenses which includes one ormore on-chip lenses in addition to the first on-chip lens and the secondon-chip lens, the one or more on-chip lenses being disposed over the oneor more color filters in addition to the first color filter and thesecond color filter.

The pixel unit may output an electrical signal of a level correspondingto a composition result of the respective spectral characteristics ofthe color filter group.

The photodiode may be constituted of a photodiode group each disposedbelow the color filter group, and electrical signals output from thepixel unit each having a level corresponding to a spectralcharacteristic of the color filter group may be added.

The pixel unit may further include a common floating diffusion that addsthe electrical signals each output from the photodiode groups.

Each of the electrical signals output from the photodiode groups may beamplified by an individually preset gain.

Each photodiode group may be individually preset with a chargeaccumulating time.

Each of the color filter groups may have a characteristic to transmitinfrared light.

A waveguide may be formed above the photodiode.

The photodiode may have a plurality of output modes which areselectively switchable through an inner or outer control of the imagesensor.

An imaging apparatus of an aspect of the present technology is mountedwith an image sensor including a pixel unit, the pixel unit includes aphotodiode; a first color filter and a second color filter each disposedin a different position on a plane above the photodiode; and a firston-chip lens disposed over the first color filter and a second on-chiplens disposed over the second color filter.

A live body imaging apparatus of an aspect of the present technologyincludes an imaging apparatus mounted with an image sensor including apixel unit, the pixel unit includes a photodiode; a first color filterand a second color filter each disposed in a different position on aplane above the photodiode; and a first on-chip lens disposed over thefirst color filter and a second on-chip lens disposed over the secondcolor filter, wherein, the imaging apparatus takes a picture of a livebody as an object.

In the image sensor of one aspect of the present technology, a pixelunit is provide in which a photodiode; a first color filter and a secondcolor filter each disposed in a different position on a plane above thephotodiode; and a first on-chip lens disposed over the first colorfilter and a second on-chip lens disposed over the second color filterare included.

In an imaging apparatus of one aspect of the present technology, animage sensor including a pixel unit is mounted, in which a photodiode; afirst color filter and a second color filter each disposed in adifferent position on a plane above the photodiode; and a first on-chiplens disposed over the first color filter and a second on-chip lensdisposed over the second color filter are included.

In a live body imaging apparatus of one aspect of the presenttechnology, an imaging apparatus is mounted with an image sensorincluding a pixel unit, in which the pixel unit includes a photodiode; afirst color filter and a second color filter each disposed in adifferent position on a plane above the photodiode; and a first on-chiplens disposed over the first color filter and a second on-chip lensdisposed over the second color filter, wherein a picture of a live bodyas an object is taken by the imaging apparatus.

As described above, according to the present technology, an optimalspectral characteristic can be created.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of a pixel unit of a generalconfiguration;

FIG. 2 is a top view of an N-divided pixel unit;

FIG. 3 illustrates an example of a configuration of a single pixel unitconfigured by applying the technique of the present technology;

FIG. 4 illustrates an example of a configuration of an N-divided pixelunit configured by applying the technique of the present technology;

FIG. 5 is a diagram showing spectral characteristics of the lightsoutput from a photodiode;

FIG. 6 illustrates an example of a configuration of a single pixel unitincluding plural color filters disposed and laminated on an identicalposition on a plane;

FIG. 7 illustrates spectral characteristics of the lights output fromthe photodiode in the single pixel unit including plural color filtersdisposed and laminated on an identical position on a plane;

FIG. 8 is a diagram showing the spectral characteristics of the lights,which are output from the photodiode in the pixel unit of aconfiguration of the present technology;

FIG. 9 illustrates the disposition of an on-chip lens;

FIG. 10 illustrates an example of a configuration of a single pixel unitof a configuration of the present technology which is formed with awaveguide;

FIG. 11 illustrates an example of a configuration of an N-divided pixelunit to which the first adding technique is applied;

FIG. 12 is a diagram showing spectral characteristics of the lightsoutput from the photodiode;

FIG. 13 illustrates an example of a configuration of an N-divided pixelunit to which a second adding technique is applied;

FIG. 14 illustrates an N-divided pixel unit of a configuration of thepresent technology in which accumulating time for each small pixel ischanged;

FIG. 15 is a top view of N-divided pixel units of a configuration of thepresent technology in which three color filters are disposed;

FIG. 16 is a diagram showing spectral characteristics of the lightsoutput from the photodiode;

FIG. 17 illustrates an example of a configuration of an N-divided pixelunit of a configuration of the present technology in which an infraredcolor filter is disposed;

FIG. 18 is a diagram showing spectral characteristics of an I-colorfilter and a J-color filter;

FIG. 19 illustrates an example of a configuration of a live bodyinformation obtaining system; and

FIG. 20 is a block diagram showing an example of a configuration of animaging apparatus to which the present technology is applied.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Embodiments of the present technology will be described below.

First of all, a description will be given on a general pixel whichconfigures an image sensor. Hereinafter, the following description willmade while assuming that the acceptance surface of an image sensor isthe upper surface, the surface opposite to the acceptance surface is thebottom surface; and direction parallel to a normal of the acceptancesurface is a vertical direction, and a direction parallel to theacceptance surface is a lateral direction.

[General Configuration of a Pixel]

FIG. 1 is a cross-sectional view of a pixel unit of a generalconfiguration.

The pixel unit means a structure which includes several composingelements, in addition to a photodiode as a pixel, a color filter, anon-chip lens and the like. Typical pixel unit includes the following twotypes.

One type is a pixel unit which has single photodiode as the pixel. Suchpixel unit will be referred below to as single pixel unit. The othertype is a pixel unit which has N (N is an integer greater than 2) ofphotodiodes as the pixels. Such pixel unit will be referred to asN-divided pixel unit.

A single pixel unit 10 shown in FIG. 1A is configured including, withrespect to one single photodiode 21, a green color filter 22 and anon-chip lens 23 which are laminated in this order from the bottom.Although not shown in the figure, between the photodiode 21 and greencolor filter 22, a light transmissive planarization film or the like maybe disposed.

A ray of light entered into the on-chip lens 23 passes through the greencolor filter 22 and is focused on the photodiode 21 and finally entersinto the photodiode 21. In more precisely, in the green color filter 22,in the light coming out from the on-chip lens 23, only the light havingspecific wavelength bands (i.e. green wavelength bands) passes throughthe green color filter 22 and enters into the photodiode 21. Thephotodiode 21 outputs an electrical signal of a level corresponding tothe amount of entered light; i.e. the amount of received light. Herenote that, for the convenience of explanation, although the color filterdisposed in the single pixel unit 10 is the green color filter 22, butthe color of the color filter is not particularly limited thereto.

An N(=2)-divided pixel unit 30 shown in FIG. 1B is configured including,with respect to a of pair neighboring two photodiodes 41-1 and 41-2, agreen color filter 42 and an on-chip lens 43 are laminated in this orderfrom the bottom. The number of the photodiodes disposed in the N-dividedpixel unit is not limited to two.

A lay of light entering the on-chip lens 43 passes through the greencolor filter 42 and is focused on the photodiodes 41-1 and 41-2, andenters thereinto. In more precisely, in the green color filter 42, inthe light coming out of the on-chip lens 43, only the light havingspecific wavelength bands (i.e. green wavelength bands) passestherethrough and enters into the photodiodes 41-1 and 41-2. Each of thephotodiodes 41-1 and 41-2 outputs an electrical signal of a levelcorresponding to the amount of entered light; i.e. the amount ofreceived light respectively.

In the N-divided pixel unit 30, an electrical signal of a levelequivalent to the sum of every levels corresponding to the amount oflight received by each of N photodiodes. Referring to FIG. 2, adescription on the output from the N-divided pixel unit 30 will be made.

[Output from the N-Divided Pixel Unit]

FIG. 2 is a top view of an N-divided pixel unit when N=4. Two techniquesare available for adding each of the electrical signals from the Nphotodiodes. FIG. 2A is a top view of an N-divided pixel unit to which afirst adding technique is applied. FIG. 2B is top view of an N-dividedpixel unit to which a second adding technique is applied. In the topviews in FIG. 2, the on-chip lens 43 and the green color filter 42 arenot shown.

As shown in FIG. 2A, in the N-divided pixel unit 30 to which the firstadding technique is applied, photodiodes 41-1 to 41-4 are disposed. In acentral position of the photodiodes 41-1 to 41-4, a common floatingdiffusion (hereinafter, referred to as common FD) section 51 isdisposed.

According to the first adding technique, the electrical signals from thephotodiodes 41-1 to 41-4, each having a level corresponding to theamount of received light, is transferred to the common FD section 51respectively. The common FD section 51 adds every electrical signals andoutputs an electrical signal of a level; i.e. the sum of each levels.Thus, in the first adding technique, each of the electrical signals fromthe N photodiodes are summed and then output therefrom.

Also, in the N-divided pixel unit 30 to which the second addingtechnique is applied, photodiodes 41-1 to 41-4 are dispose same as thosein FIG. 2A as shown in FIG. 2B. Each of the photodiodes 41-1 to 41-4 isprovided with an individual floating diffusion (hereinafter, referred toas individual FD) section 61-1 to 61-4 respectively.

According to the second adding technique, each of the electrical signalsof a level corresponding to the amount of light received by therespective photodiodes 41-1 to 41-4 is transferred to each of theindividual FD sections 61-1 to 61-4. All of the electrical signals areseparately output from the individual FD sections 61-1 to 61-4, and areadded in an image signal reading section (not shown). Thus, in thesecond adding technique, the electrical signals from each of the Nphotodiodes is summed after being output from the individual FD sections61-1 to 61-4.

In the N-divided pixel unit, even when either the first adding techniqueor the second adding technique is applied thereto, since an electricalsignal of a level, in which all levels corresponding to the amount ofreceived light from each of the N photodiodes are summed ultimatelyresulting in one electrical signal from one pixel, and is outputtherefrom.

As described above, both of the single pixel unit 10 of a generalconfiguration and the N-divided pixel unit 30 are provided with onecolor filter and a single on-chip lens.

The spectral characteristic of the light focused on each photodiodedepend on the spectral characteristics of the color filters disposed onthe respective photodiodes. Therefore, for improving the S/N ratio andthe color reproducibility, a new color filter is desired to bedeveloped. However, as described above, to develop a new color filter,an enormous time and cost are necessary. Also, even if a new materialfor color filter is developed, it is difficult to optimize the spectralcharacteristic of the light focused on the photodiode of each pixel tobe suitable to the purpose of application.

On the other hand, an image sensor which has an emerald pixel withenhanced color reproducibility is known. Contrarily to the known imagesensors which have three primary color pixels of R-pixel, G-pixel andB-pixel, the image sensor having the emerald pixel is an image sensorhaving a configuration of four primary color pixels, in which the ratioof G-pixels is reduced but equivalent amount of emerald pixels areadded. However, compared to known image sensors, in the image sensorhaving emerald pixels, since G-pixels are reduced as described above,the resolution may be deteriorated proportionally.

Also, there is known a technique to estimate right source based on pixelvalues of R-pixel, G-pixel and B-pixel. However, new light sources suchas white LED are increasingly used. Estimation of the light source isgetting difficult.

The inventor of the technology has developed a technique to laminateplural color filters and plural on-chip lenses in deferent positions ona plane of one pixel unit. Here, the position on a plane means aposition on a two-dimensional plane parallel to the acceptance surfaceof the image sensor, which is a position determined by coordinatesindicating pixel position on the image sensor. Hereinafter, suchtechnique will be referred to as technique of the present technology. Byapplying the technique of the present technology, an optimal spectralcharacteristic can be created.

Referring to FIG. 3 and FIG. 4, a description will be made on a singlepixel unit and an N-divided pixel unit which are configured by applyingthe technique of the present technology.

[Single Pixel Unit Configured by Applying the Technique of the PresentTechnology]

FIG. 3 is an illustration showing an example of the configuration of asingle pixel unit configured by applying the technique of the presenttechnology. At the left side in FIG. 3, a single pixel unit 10 of ageneral configuration is shown. At the right side in FIG. 3, a singlepixel unit 100 configured by applying the technique of the presenttechnology is shown.

At the upper-left in FIG. 3, a top view of a group of neighboring foursingle pixel units 10 to 13 of a general configuration is shown. Notethat the on-chip lens is omitted in the top views shown in FIG. 3 orlater. The single pixel unit 10 is disposed with a green color filter22. A single pixel unit 11 is disposed with a blue color filter 25. Asingle pixel unit 12 is disposed with a red color filter 26. A singlepixel unit 13 is disposed with a green color filter 27.

A cross-sectional view of the single pixel unit 10 of a generalconfiguration taken along a line L-L′ is shown at lower-left in FIG. 3.As described referring to FIG. 1A, the single pixel unit 10 of a generalconfiguration is configured including, with respect to a singlephotodiode 21, a single green color filter 22 and a single on-chip lens23 being laminated in this order from the bottom.

By applying the technique of the present technology to the single pixelunits 10 and 13 of a general configuration, single pixel units 100 and103 of configuration shown at the right side in FIG. 3 (hereinafter,referred to as single pixel units 100 and 103 of a configuration of thepresent technology) are obtained. That is, the single green colorfilters 22 and 27 disposed on the single pixel units 10 and 13 aredivided into four respectively, and the 4-divided green color filters 22and 27 are replaced with A-color filters and B-color filters of a numberof ratio 1:1 (i.e. two each). With this, plural color filters aredisposed in different positions on a plane in one pixel unit.

A top view of a group of the single pixel units 100 and 103 of aconfiguration of the present technology and the single pixel units 101and 102 of a general configuration is shown in upper-right of FIG. 3.

The single pixel unit 100 of a configuration of the present technologyis disposed with A-color filters 112-UR and 112-DR and B-color filters112-UR and 112-DL. Here, the A-color filter means a filter whichtransmits only the light of wavelength bands of A-color in the lightcoming out of the on-chip lens. On the other hand, the B-color filtermeans a filter which transmits only the light of wavelength bands ofB-color different from the wavelength bands of A-color in the lightcoming out of the on-chip lens. Both of the A-color filter and theB-color filter are replaced with general green color filtersrespectively. Therefore, the A-color filter and the B-color filter arecolor filters which transmit the light of wavelength bands in anarbitrary range (i.e., a first range and a second range different fromthat) within the wavelength bands that the general green color filtertransmits the light (approximately, a range of 500 to 570 nm).

Likewise, the single pixel unit 103 of a configuration of the presenttechnology is dispose with A-color filters 117-UL and 117-DR, andB-color filters 117-UR and 117-DL. That is, the single pixel units 100and 103 of a configuration of the present technology are disposed withthe A-color filters and the B-color filters of a number with the ratio1:1 (i.e. two each).

Same as the single pixel unit 11 of a general configuration shown at theupper-left in FIG. 3, the single pixel unit 101 of a generalconfiguration is disposed with the blue color filter 115. Also, thesingle pixel unit 102 of a general configuration is disposed with a redcolor filter 116 same as the single pixel unit 12 of a generalconfiguration shown at the upper-left in FIG. 3.

A cross-sectional view of the single pixel unit 100 of a configurationof the present technology taken along a line L-L′ is shown at thelower-right in FIG. 3.

The single pixel unit 100 of a configuration of the present technologyis configured including, with respect to the single photodiode 111, apair of the A-color filter 112-UL and the B-color filter 112-UR, a pairof an on-chip lens 113-UL and an on-chip lens 113-UR being laminated inthis order from the bottom. That is, above the A-color filter 112-UL,the on-chip lens 113-UL is disposed; and above the B-color filter112-UR, the on-chip lens 113-UR is disposed.

As described above, in the example of FIG. 3, in the single pixel unit100 of a configuration of the present technology, as for the colorfilter disposed over the single photodiode 111, 2 types of color filterssuch as the A-color filters 112-UR and 112-DR and the B-color filters112-UR and 112-DL are employed, and color filters of identical type aredisposed on a diagonal line. However, the color filter employed for thesingle pixel unit of a configuration of the present technology is notparticularly limited to the example in FIG. 3, but plural color filtersof two or more types may be arbitrary employed.

[N-Divided Pixel Unit Configured by Applying the Technique of ThePresent Technology]

FIG. 4 illustrates an example of a configuration of an N-divided pixelunit configured by applying the technique of the present technology. TheN-divided pixel unit 30 of a general configuration is shown at the leftside in FIG. 4; an N-divided pixel unit 100 a configured by applying thetechnique of the present technology is shown at the right side in FIG.4.

A top view of a group of neighboring four N-divided pixel units 30 to 33of a general configuration is shown at the upper-left in FIG. 4. TheN-divided pixel unit 30 is disposed with the green color filter 42. TheN-divided pixel unit 31 is disposed with the green color filter 45. TheN-divided pixel unit 32 is disposed with the green color filter 46. TheN-divided pixel unit 33 is disposed with the green color filter 47.

A cross-sectional view of the N-divided pixel unit 30 of a generalconfiguration taken along line L-L′ is shown at the lower-left in FIG.4. As described referring to FIG. 1B, the N-divided pixel unit 30 of ageneral configuration is configured including, with respect to the apair of neighboring two photodiodes 41-1 and 41-2, a single green colorfilter 42 and a single on-chip lens 43 being laminated in this orderfrom the bottom.

By applying the technique of the present technology to the N-dividedpixel units 3 and 33 of a general configuration, N-divided pixel units100 a and 103 a of a configuration of the present technology shown atthe right side in FIG. 4 are obtained. That is, the single green colorfilters 42 and 47 disposed on the N-divided pixel units 30 and 33 aredivided into four respectively; the four divided green color filters 42and 47 are replaced with the A-color filter and the B-color filter of anumber with the ratio 1:1 (i.e. two each) respectively. With this,plural color filters are disposed in different positions on a planewithin one pixel unit.

A top view of a group of the N-divided pixel units 100 a and 103 a of aconfiguration of the present technology and the N-divided pixel units101 a and 102 a of a general configuration is shown at the upper-rightin FIG. 4.

The N-divided pixel unit 100 a of a configuration of the presenttechnology is disposed with A-color filters 112 a-UL and 112 a-DR andB-color filters 112 a-UR and 112 a-DL. Likewise, the single pixel unit103 of a configuration of the present technology is disposed withA-color filters 117 a-UL and 117 a-DR and B-color filters 117 a-UR and117 a-DL. That is, the N-divided pixel units 100 a and 103 a of aconfiguration of the present technology is disposed with the A-colorfilters and the B-color filters of a number with the ratio of 1:1 (i.e.two each).

Same as the N-divided pixel unit 31 of a general configuration shown atthe upper-left in FIG. 4, the N-divided pixel unit 101 a of a generalconfiguration is disposed with a blue color filter 115 a. Also, same asthe N-divided pixel unit 32 of a general configuration shown at theupper-left in FIG. 4, the N-divided pixel unit 102 a of a generalconfiguration, is disposed with a red color filter 116 a.

A cross-sectional view of the N-divided pixel unit 100 a of aconfiguration of the present technology taken along a line L-L′ is shownat the lower-right in FIG. 4.

The N-divided pixel unit 100 a of a configuration of the presenttechnology is configured including, with respect to a pair ofneighboring two photodiodes 111 a-UL and 111 a-UR, a pair of an A-colorfilters 112 a-UL and a B-color filters 112 a-UR, and a pair of anon-chip lens 113 a-UL and an on-chip lens 113 a-UR being laminated inthis order from the bottom. That is, the photodiode 111 a-UL, theA-color filters 112 a-UL and the on-chip lens 113 a-UL are disposed inthis order from the bottom; and the photodiode 111 a-UR, the B-colorfilters 112 a-UR and the on-chip lens 113 a-UR are disposed in orderfrom the bottom.

As described above, in the example in FIG. 4, in the N-divided pixelunit 100 a of a configuration of the present technology, as for thecolor filter disposed over the N photodiodes, two types of color filterssuch as the A-color filters 112 a-UL and 112 a-DR and the B-colorfilters 112 a-UR and 112 a-DL are employed, and color filters ofidentical type are disposed on a diagonal line. The color filteremployed for the N-divided pixel unit of a configuration of the presenttechnology is not particularly limited to the example in FIG. 4, but twoor more kinds of plural color filters may be arbitrary employed.

[Spectral Characteristic of the Output Light]

In the pixel unit of a configuration of the present technology; i.e. inthe pixel unit in which plural color filters is disposed in differentpositions on a plane within one pixel unit, the electrical signal outputfrom the photodiode is a result of combination of spectralcharacteristics of plural color filters as shown in FIG. 5.

FIG. 5 is a diagram showing spectral characteristics of the light outputfrom the photodiode in the pixel unit of a configuration of the presenttechnology. In FIG. 5, the vertical axis represents the transmissivity;and the horizontal axis represents the wavelength.

The A-color filters 112-UR and 112-DR disposed on the single pixel unit100 of a configuration of the present technology has a characteristicthat the transmissivity is the highest in a range of wavelength 520 to540 nm as indicated with a solid line. The B-color filters 112-UR and112-DL disposed on the single pixel unit 100 of a configuration of thepresent technology has a characteristic that the transmissivity is thehighest in a range of wavelength 530 to 580 nm as indicated with adotted line.

The photodiode 111 disposed on the single pixel unit 100 of aconfiguration of the present technology receives the light passingthrough the A-color filters 112-UR and 112-DR and the B-color filters112-UR and 112-DL which have the above characteristics. In this case, itis the spectral characteristic of the light as the result of combinationof the characteristics of the A-color filters 112-UR and 112-DR and theB-color filters 112-UR and 112-DL that enters the photodiode 111; i.e. acharacteristic of spectroscopic output C indicated with a dotted line inFIG. 5. Accordingly, in the single pixel unit 100 of a configuration ofthe present technology, the photodiode 111 outputs an electrical signalof a level corresponding to the spectroscopic output C.

Likewise, the N photodiodes disposed on the N-divided pixel unit 100 aof a configuration of the present technology receives the light passingthrough the A-color filters 112 a-UL and 112 a-DR and the B-colorfilters 112 a-UR and 112 a-DL which has the characteristics shown inFIG. 5. In this case, when every spectral characteristics of the lightentering the N photodiodes are combined, a result of combination ofcharacteristics of the A-color filters 112 a-UL and 112 a-DR and theB-color filters 112 a-UR and 112 a-DL is obtained; i.e., thecharacteristic of the spectroscopic output C indicated with a dottedline in FIG. 5 are obtained. Accordingly, in the N-divided pixel unit100 a of a configuration of the present technology, an electrical signalof a level as a sum of every levels corresponding to the amount of lightreceived by the N photodiodes; i.e. an electrical signal of a levelcorresponding to the spectroscopic output C is output from a common FDsection 201 (describe below) or an image signal reading section (forexample, the image signal reading section at the downstream (forexample, the image signal reading section 533 shown in FIG. 20, whichwill be described below).

As described above, the single pixel unit 100 and the N-divided pixelunit 100 a each of a configuration of the present technology areconfigured including the A-color filters and the B-color filters whichhave the characteristics shown in FIG. 5, which are disposed with theratio of 1:1 at different positions on a plane in one pixel unit. Withthis, the light focused on the photodiode disposed on the single pixelunit 100 has the characteristic of the spectroscopic output C indicatedwith the dotted line in FIG. 5. When every spectral characteristics ofthe light entering the N photodiodes of the N-divided pixel unit 100 aare combined, the characteristic of the spectroscopic output C indicatedwith the dotted line in FIG. 5 is obtained. That is, with the singlepixel unit 100 the N-divided pixel unit 100 a which have theconfiguration of the present technology, a new spectral characteristic(i.e., the characteristic of the spectroscopic output C) can be createddifferent from the original spectral characteristics caused through thematerials for the A-color filter and the B-color filter. That is, a newspectral characteristic can be created without depending on thedevelopment of a material for a new color filter.

However, for example, when plural color filters disposed and laminatedon an identical position on a plane in one pixel unit, the spectralcharacteristic of the light output from the photodiode is a result ofintegration of spectral characteristics of the plural color filterslaminated at the identical position on a plane. A detailed descriptionon this point will be made referring to FIG. 6 and FIG. 7.

[Plural Color Filters Disposed at an Identical Position on a Planewithin the Pixel Unit]

FIG. 6 illustrates an example of a configuration of a single pixel unitincluding plural color filters disposed and laminated on an identicalposition on a plane.

The single pixel unit 10 of a general configuration is shown at the leftside in FIG. 6. Since the description of the single pixel unit 10 of ageneral configuration has been made referring to FIG. 1A etc, thedescription thereof is omitted here.

With respect to the single pixel unit 10 of a general configuration, asingle pixel unit 120 including plural color filters disposed andlaminated on an identical position on a plane is shown at the right sidein FIG. 6.

In particular, the figure at the upper-right side in FIG. 6 is a topview of a group of a single pixel unit including single pixel units 120and 123 in which plural color filters are disposed and laminated on anidentical position on a plane. The figure at the lower-right side inFIG. 6 is a cross-sectional view of the single pixel unit 120 takenalong a line L-L′.

As shown in the figures at the upper-right side and at the lower-rightin FIG. 6, the single pixel unit 120 is configured including, withrespect to the single photodiode 131, a B-color filter 132, an A-colorfilter 133 and a pair of an on-chip lens 134-L and an on-chip lens 134-Rbeing laminated in this order from the bottom. That is, at the identicalposition on a plane disposed with the photodiode 131, the B-color filter132 and the A-color filter 133 are disposed and laminated.

[Spectral Characteristic of the Output Light]

FIG. 7 illustrates spectral characteristics of the light output from thephotodiode 131 in the single pixel unit 120 including plural colorfilters disposed and laminated on an identical position on a plane asdescribed above. In FIG. 7, the vertical axis represents thetransmissivity; and the horizontal axis represents the wavelength.

The A-color filter 133 disposed on the single pixel unit 120 has acharacteristic in which the transmissivity is the highest around 600 nmof wavelength as indicated with a solid line in FIG. 7. The B-colorfilter 132 disposed on the single pixel unit 120 has a characteristic inwhich the transmissivity is the highest around 500 nm of wavelength asindicated with a dotted line. The photodiode 131 disposed on the singlepixel unit 120 receives the light passing through the two color filtersof the A-color filter 133 and the B-color filter 132 each having theabove characteristic.

In this case, the light entering the photodiode 131 is a result ofintegration of the characteristic of the B-color filter 132 and thecharacteristic of the A-color filter 133; i.e., the characteristic ofspectroscopic output T indicated with a dotted line in FIG. 7. Thereason of this is that, when plural color filters are disposed at anidentical position on a plan in the single pixel unit 120, a spectralabsorption occurs in each of the plural color filters. Therefore, onlythe electrical signal of a level corresponding to the result ofintegration of the spectral characteristics of all color filterspositioned at the identical position on a plane in the single pixel unit120 is output from the photodiode 131.

[Spectral Characteristic of the Light Output from the Pixel Unit Havinga Configuration of the Present Technology]

Contrarily, when the A-color filter and the B-color filter shown in FIG.7 are used, in the pixel unit of a configuration of the presenttechnology, the spectral characteristic of the light output from thephotodiode is as shown in FIG. 8.

FIG. 8 is a diagram showing the spectral characteristic of the lightoutput from the photodiode in the pixel unit of a configuration of thepresent technology. In FIG. 8, the vertical axis represents thetransmissivity; and the horizontal axis represents the wavelength.

As shown in FIG. 8, the A-color filter and the B-color filter disposedon the pixel unit of a configuration of the present technology have thesame characteristics as those of the A-color filter 133 and the B-colorfilter 132 disposed on the single pixel unit 120 which has beendescribed referring to FIG. 7.

The light that enters the photodiode 111 disposed in the single pixelunit 100 of a configuration of the present technology is the light thatpasses through each of the A-color filters 112-UR and 112-DR and theB-color filters 112-UR and 112-DL, each having the characteristic asdescribed above. In this case, the spectral characteristic of the lightthat enters the photodiode 111 is a composition result of thecharacteristics of the A-color filters 112-UR and 112-DR and the B-colorfilters 112-UR and 112-DL; i.e., the characteristic of the spectroscopicoutput C indicated with a dotted line in FIG. 8. Accordingly, in thesingle pixel unit 100 of a configuration of the present technology, thephotodiode 111 outputs an electrical signal of a level corresponding tothe spectroscopic output C.

Likewise, the light that enters the N photodiodes disposed in theN-divided pixel unit 100 a of a configuration of the present technologyis the light that passes through the A-color filters 112 a-UL and 112a-DR and the B-color filters 112 a-UR and 112 a-DL, each having thecharacteristic shown in FIG. 8. In this case, the composition result ofthe spectral characteristics of the light that enters the N photodiodesis the composition result of the characteristics of the A-color filters112 a-UL and 112 a-DR and the B-color filters 112 a-UR and 112 a-DL;i.e., the characteristic of the spectroscopic output C indicated with adotted line in FIG. 8. Accordingly, in the N-divided pixel unit 100 a ofa configuration of the present technology, an electrical signal that hasa level in which all levels corresponding to the amount of lightreceived by each of the N photodiodes. That is, an electrical signal ofa level corresponding to the spectroscopic output C is output from acommon FD section 201 (described below) or the image signal readingsection at the downstream (for example, the image signal reading section533 shown in FIG. 20, which will be described below).

As described above referring to FIG. 3 to FIG. 8, in the single pixelunit 100 and the N-divided pixel unit 100 a which have the configurationof the present technology, plural color filters are disposed atdifferent positions on a plane in one pixel unit. Accordingly, a newspectral characteristic can be created without depending on thedevelopment of a material for a new color filter.

Here, defining that a unit that receives the light passing through onecolor filter is a pixel, when plural color filters are disposed atdifferent positions on a plane of one pixel unit, one pixel is includedin each of the plural color filters. That is, plural pixels are includedin one pixel unit. In order to distinguish the plural pixels included inone pixel unit from a general pixel, the same will be hereinafterreferred to as small pixels.

[Dispassion of the On-Chip Lens]

As described referring to FIG. 3 and FIG. 4, in the single pixel unit100 and the N-divided pixel unit 100 a which have the configuration ofthe present technology, the on-chip lens is disposed for each of theplural color filters disposed at the different positions on a plane inone pixel unit; i.e., the on-chip lens is disposed for each small pixel.

FIG. 9 illustrates a disposition of the on-chip lenses.

A figure at left end in FIG. 9 illustrates a single pixel unit 10 of ageneral configuration. Since the description on the single pixel unit 10of a general configuration has been given referring to FIG. 1A etc, thedescription thereof is omitted here.

The second figure from the left in FIG. 9 is a top view of a group ofthe single pixel units 150 and 153, which include plural color filtersdisposed at different positions on a plane in one pixel unit, and thesingle pixel units 151 and 152 of a general configuration. The bottomfigure is a cross-sectional view of the single pixel unit 150 takenalong line L-L′. The single pixel unit 150 is configured including, withrespect to a single photodiode 161, a pair of an A-color filter 162-ULand a B-color filter 162-UR and a single on-chip lens 163 beinglaminated in this order from the bottom.

As shown in the second figure in FIG. 9, in the single pixel unit 150,with respect to the single photodiode 161, although plural color filtersare disposed, only one on-chip lens 163 is disposed. In this case, whenthe light enters the on-chip lens 163 from an oblique direction, theamount of the light passing through the plural color filters is notuniform. Accompanying this, the spectral characteristic of the lightentering the photodiode 161 also varies. That is, the spectralcharacteristic of the light entering the photodiode 161 varies dependingon the entering angle of the light which enters the on-chip lens 163.For example, as shown in the example of the second figure from the leftin FIG. 9, the amount of the light passing through the B-color filter162-UR is larger than the amount of the light passing through theA-color filter 162-UL. Thus, the spectral characteristic of the lightentering the photodiode 161 varies.

Therefore, as shown in the third and fourth figures from the left inFIG. 9, in the single pixel unit 100 and the N-divided pixel unit 100 awhich have the configuration of the present technology, the on-chip lensis disposed for the plural color filters disposed at different positionson a plane in one pixel unit; i.e., disposed for each small pixel.

In the single pixel unit 100 of a configuration of the presenttechnology, the on-chip lens 113-UL is dispose on the A-color filter112-UL; and the on-chip lens 113-UR is disposed on the B-color filter112-UR. With this, unevenness of the amount of the light passing throughthe A-color filter 112-UL and the B-color filter 112-UR is reduced, andthus variation of the spectral characteristic of the light entering thephotodiode 111 is reduced.

Likewise, in the N-divided pixel unit 100 a of a configuration of thepresent technology also, the on-chip lens 113 a-UL is disposed on theA-color filters 112 a-UL; and the on-chip lens 113 a-UR is disposed onthe B-color filters 112 a-UR. With this, unevenness of the amount of thelight passing through the A-color filters 112 a-UL and the B-colorfilters 112 a-UR is reduced, and thus variation of spectralcharacteristic of the light entering the photodiode 111 a-UL and thephotodiode 111 a-UR is reduced.

By disposing plural color filters and plural on-chip lens at differentpositions on a plane in one pixel unit as described above, the lightfocused on the photodiode disposed in each pixel unit is opticallycombined. With this, the spectral characteristic of the light focused oneach photodiode can be controlled to be optimally suitable for thepurpose of application.

[Example of a Configuration of Single Pixel Unit of a Configuration ofthe Present Technology Formed with a Waveguide]

In the photodiode disposed in one pixel unit may not ensure a uniformphotoelectric conversion due to non-uniformity of ion implantation orthe like. Unevenness may be generated in the sensitivity of thephotodiode.

FIG. 10 illustrates an example of a configuration of a single pixel unitof a configuration of the present technology formed with a waveguide.

The single pixel unit 10 of a general configuration is shown at the leftside in FIG. 10. The description of the single pixel unit 10 of ageneral configuration has been made referring to FIG. 1A etc. Thedescription thereof is omitted here.

In the center of FIG. 10, the single pixel unit 100 of a configurationof the present technology is shown. The description of the single pixelunit 100 of a configuration of the present technology has been madereferring to the figure at the right side in FIG. 3. The descriptionthereof is omitted here.

It is assumed that the photodiode 111 has unevenness in the sensitivitysuch that, for example, the edge area of the acceptance surface has alow sensitivity; and the central area thereof has a high sensitivity asshown in the center-bottom figure in FIG. 10. In this case, for example,even when the light intensity is the same between the light which passesthrough the A-color filter 112-UL and enters the edge area of thephotodiode 111 and the light which passes through the B-color filter112-UR and enters the central area of the photodiode 111, the lightintensity in the central area is higher that that in the edge area; andan electrical signal of higher level is output in the central area.

Therefore, when unevenness is found in the sensitivity of the photodiode111 as shown in the center low figure in FIG. 10, for example, awaveguide 169 is disposed over the photodiode 111 as shown in the figureat the lower-right in FIG. 10. With this, the light passing through theA-color filter 112-UL and the light passing through the B-color filter112-UR is once collected by the waveguide 169 and is allowed to enterthe central area of the photodiode 111 having higher sensitivity.Therefore, when the light intensity is the same between the lightpassing through the A-color filter 112-UL and the light passing throughthe B-color filter 112-UR, output electrical signals have the samelevel.

By disposing the waveguide 169 in the single pixel unit 100 of aconfiguration of the present technology as described above, the lightfocused on the photodiode 111 is optically combined while reducing theinfluence by the unevenness of the sensitivity in the photodiode 111.With this, the spectral characteristic of the light focused on eachphotodiode can be controlled optimally to be suitable for the purpose ofapplication.

As described above, with the pixel unit of a configuration of thepresent technology, the spectral characteristic of the light focused onthe photodiode can be controlled by optically combining the light. Adescription will be made below while giving an example to control thespectral characteristic of the light focused on the photodiode byelectrically combining the light.

[N-Divided Pixel Unit to which First Adding Technique is Applied]

In the N-divided pixel unit, an electrical signal having a level, inwhich every levels each corresponding to the amount of received light ofthe N photodiodes are added, is output. As described above, as for thetechnique to add each of the electrical signals of the N photodiodes, afirst technique and a second technique area available.

FIG. 11 illustrates an example of a configuration of an N-divided pixelunit to which the first adding technique is applied.

An N-divided pixel unit 170 of a general configuration, to which thefirst adding technique is applied, is shown at the left side in FIG. 11.An N-divided pixel unit of a configuration of the present technology 100b, to which the first adding technique is applied, is shown at the rightside in FIG. 11.

The figure at the upper-left in FIG. 11 is a top view of a group ofneighboring four N-divided pixel units 170 to 173 of a generalconfiguration to which the first adding technique is applied.

The N-divided pixel unit 170 is disposed with four green color filters182-UL, 182-UR, 182-DL and 182-DR. Each of the four green color filtersis disposed with a transfer gate 200 indicated with a triangle. And atthe central portion of the four green color filters, a common FD section201 is disposed.

The N-divided pixel unit 171 is disposed with four blue color filters185-UL, 185-UR, 185-DL and 185-DR. Each of the four green color filtersis disposed with a transfer gate 200. And at the central portion of thefour green color filters, a common FD section 201 is disposed.

The N-divided pixel unit 172 is disposed with four red color filters186-UL, 186-UR, 186-DL and 186-DR. Each of the four green color filtersis disposed with a transfer gate 200. And at the central portion of thefour green color filters, a common FD section 201 is disposed.

The N-divided pixel unit 172 is disposed with four green color filters187-UL, 187-UR, 187-DL and 187-DR. Each of the four green color filtersis disposed with a transfer gate 200. And at the central portion of thefour green color filters, a common FD section 201 is disposed.

As shown in the figure at the lower-left in FIG. 11, in accordance withthe first adding technique, electrical signals of a level correspondingto the amount of the lights, which are received by the four greenphotodiodes 181-UL, 181-UR, 181-DL and 181-DR of the N-divided pixelunit 170, are transferred to the transfer gate 200, and then to thecommon FD section 201 respectively. The common FD section 201 outputs asignal equivalent to every electrical signals added; i.e., an electricalsignal having a level equivalent to every levels summed. The common FDsection 201 simultaneously reads every charge accumulated to thereby addthe electrical signals of a level corresponding to the read charge.Thus, according the first adding technique, the every electrical signalsof various levels from each of the N (in this case, 4) photodiodes areadded; and the N-divided pixel unit 170 outputs an electrical signal ofa level after the summation.

Likewise, in the N-divided pixel units 171 to 173 also, electricalsignals of a level corresponding to the amount of the light received bythe respective photodiodes are transferred to each transfer gate 200;and each signal is transferred to the common FD section 201. Each of theN-divided pixel units 171 to 173 outputs an electrical signal of a levelafter summation of every electrical signals made by the common FDsection 201.

The figure at the upper-right in FIG. 11 is a top view of a group of theN-divided pixel units 100 b and 103 b of a configuration of the presenttechnology and the N-divided pixel units 101 b and 102 b of a generalconfiguration to which the first adding technique is applied.

The N-divided pixel unit 100 b of a configuration of the presenttechnology is disposed with the A-color filters 112 b-UL and 112 b-DRand the B-color filters 112 b-UR and 112 b-DL. Each of the four colorfilters is disposed with a transfer gate 210 indicated with a triangle.Further in the central portion of the four color filters, a common FDsection 211 is disposed.

The N-divided pixel unit 101 b of a general configuration is disposedwith four blue color filters 115 b-UL, 115 b-UR, 115 b-DL and 115 b-DR.Each of the four color filters is provided with the transfer gate 210.Further, in the central portion of the four color filters, the common FDsection 211 is disposed.

The N-divided pixel unit 102 b of a general configuration is disposedwith red color filters 116 b-UL, 116 b-UR, 116 b-DL and 116 b-DR. Eachof the four color filters is provided with the transfer gate 210.Further, in the central portion of the four color filters, the common FDsection 211 is disposed.

The N-divided pixel unit 103 b of a configuration of the presenttechnology is disposed with the B-color filters 117 b-UL and 117 b-DRand the A-color filter 117 b-UR and 117 b-DL. Each of the four colorfilters is provided with the transfer gate 210. Further, in the centralportion of the four color filters, the common FD section 211 isdisposed.

As shown in the figure at the lower-right in FIG. 11, in accordance withthe first adding technique, the electrical signals of a levelcorresponding to the amount of the light received by the A-photodiodes111 b-UL and 111 b-DR and B-photodiodes 111 b-UR and 111 b-DL of theN-divided pixel unit 100 b of a configuration of the present technologyare transferred to each transfer gate 210, and then to the common FDsection 211 respectively. The N-divided pixel unit 100 b outputs asignal equivalent to every electrical signals added; i.e., an electricalsignal of a level equivalent to the sum of the signals of various levelsare summed by the common FD section 211. The common FD section 211simultaneously reads every charge accumulated to thereby add electricalsignals of a level equivalent to the read charge.

Likewise, in the N-divided pixel units 101 b to 103 b also, electricalsignals of various levels corresponding to the amount of the lightreceived by the respective photodiodes are transferred to each transfergate 210, and then transferred to the common FD section 211.

In this case, the spectral characteristic of the light output from theN-divided pixel units 100 b and 103 b of a configuration of the presenttechnology has a characteristic of the spectroscopic output C indicatedwith the dotted line in FIG. 5. That is, the N-divided pixel units 100 band 103 b outputs an electrical signal of a level corresponding to thecomposition result of the spectral characteristics of the plural colorfilters disposed at the different positions on a plane in the N-dividedpixel units 100 b and 103 b. That is, with the N-divided pixel units 100b and 103 b of a configuration of the present technology, a new spectralcharacteristic, which is different from the original spectralcharacteristics obtained by the material for the A-color filter and theB-color filter, can be created.

[Adjustment of Spectral Characteristic using a Gain]

In the N-divided pixel units 100 b and 103 b of a configuration of thepresent technology shown at the right side in FIG. 11, the common FDsection 211 simultaneously reads the electrical signals of the pluralphotodiodes each having different level corresponding to the amount ofreceived light and simply adds the electrical signals. However, thecommon FD section 211 may read electrical signals at different timingfor each of the photodiodes which receives the light having identicalspectral characteristic, and add the electrical signals the level ofwhich being amplified with an individually preset gain.

Here, it is assumed that, in the N-divided pixel units 100 b and 103 bof a configuration of the present technology shown at the right side inFIG. 11, the A-color filters and the B-color filters, which are disposedwith a number of 1:1 ratio, are replaced with, for example, D-colorfilters and E-color filters respectively, each having a characteristicshown in FIG. 12.

FIG. 12 shows the spectral characteristics of the lights output from thephotodiodes in the N-divided pixel units 100 b and 103 b of aconfiguration of the present technology which are disposed with theD-color filters and E-color filters with a number 1:1 ratio. In FIG. 12,the vertical axis represents the transmissivity; and the horizontal axisrepresents the wavelength.

The D-color filter disposed in the N-divided pixel units 100 b and 103 bof a configuration of the present technology has a characteristic suchthat the transmissivity is highest in a range of 520 to 540 nm ofwavelength as indicated with a solid line in FIG. 12. Also, the E-colorfilter disposed in the N-divided pixel units 100 b and 103 b of aconfiguration of the present technology has a characteristic such thatthe transmissivity is highest in a range of 540 to 590 nm of wavelengthas indicated with a solid line in FIG. 12.

In this case, the common FD section 211 disposed in the N-divided pixelunits 100 b and 103 b of a configuration of the present technology mayread, at different timing, electrical signals of a level correspondingto the spectral characteristic of the D-color filter and the E-colorfilter and directly add these electrical signals. With this, electricalsignals of the same number as the color filter types; i.e., in thiscase, two different electrical signals can be obtained.

The common FD section 211 may also read electrical signals at differenttiming for each photodiode which receives the light having an identicalspectral characteristic, and then add the electrical signals of a levelamplified by an individually preset gain. The gain is set by the imagesignal reading section at the downstream (for example, the image signalreading section 533 shown in FIG. 20, which will be described below).

For example, when the gain of the electrical signal of a levelcorresponding to the amount of received light which passes through theE-color filter and enters the photodiode is set to 5 times, thetransmissivity has a characteristic such that the spectroscopic output Fis amplified by 5 times in range of 540 to 590 nm of wavelength asindicated with a chain line in FIG. 12.

Therefore, in the N-divided pixel units 100 b and 103 b of aconfiguration of the present technology, a composition result of thespectral characteristic of the color filter D and the spectralcharacteristic in which the gain of the color filter E is amplified by 5times; i.e., an electrical signal of a level which corresponds to thecharacteristic of the spectroscopic output F indicated with a dottedline in FIG. 12 is output. As described above, after reading electricalsignals at different timing for each photodiode which receives the lightof identical spectral characteristic, the electrical signals, the levelof which is amplified by an individually preset gain, are added; therebya new spectral characteristic can be created. Thus, by electricallycombining the spectral characteristics of plural color filters, thespectral characteristic can be optimally controlled to be suitable forthe purpose of application.

[N-Divided Pixel Unit to which Second Adding Technique is Applied]

Subsequently, a description will be made on an N-divided pixel unit towhich a second adding technique is applied.

FIG. 13 illustrates an example of a configuration of the N-divided pixelunit to which the second adding technique is applied.

The upper figure in FIG. 13 is a top view of a group of N-divided pixelunits 100 c and 103 c of a configuration of the present technology, towhich the second adding technique is applied, and N-divided pixel units101 c and 102 c of a general configuration.

In the N-divided pixel unit 100 c of a configuration of the presenttechnology, A-color filters 112 c-UL and 112 c-DR and B-color filters112 c-UR and 112 c-DL are disposed. Also, each of the four color filtersis provided with a transfer gate, which is indicated with a triangle,and an individual FD section 220. That is, the transfer gate and theindividual FD section 220 are laminated at the same position.

In the N-divided pixel unit 101 c of a general configuration, four bluecolor filters 115 c-UL, 115 c-UR, 115 c-DL and 115 c-DR are disposed.Also, each of the four color filters is provided with a transfer gateand an individual FD section 220.

In the N-divided pixel unit 102 c of a general configuration, four redcolor filters 116 c-UL, 116 c-UR, 116 c-DL and 116 c-DR are disposed.Also, each of the four color filters is provided with a transfer gateand an individual FD section 220.

In the N-divided pixel unit 103 c of a configuration of the presenttechnology, B-color filters 117 c-UL and 117 c-DR and A-color filters117 c-UR and 117 c-DL are disposed. Also, each of the four color filtersis provided with a transfer gate and an individual FD section 220.

According to the second adding technique, the electrical signals of adifferent level corresponding to the amount of received light at each ofthe A-photodiodes 111 c-UL and 111 c-DR and B-photodiodes 111 c-UR and111 c-DL in the N-divided pixel unit 100 c of a configuration of thepresent technology are transferred to the transfer gate and theindividual FD section 220 respectively as shown in the bottom figure inFIG. 13. Every electrical signals are separately output from each of thetransfer gate and the individual FD sections 220, and are added by theimage signal reading section at the downstream (for example, the imagesignal reading section 533 shown in FIG. 20, which will be describedbelow).

Likewise, in the N-divided pixel units 101 c to 103 c also, theelectrical signals each having a different level corresponding to theamount of received light at the respective photodiodes are transferredto the transfer gate and the individual FD section 220 respectively, andthen added by the image signal reading section at the downstream (forexample, the image signal reading section 533 shown in FIG. 20, whichwill be described below).

In this case, the spectral characteristic of the light output from theN-divided pixel units 100 c and 103 c of a configuration of the presenttechnology has a characteristic indicated with a dotted line in FIG. 5.That is, an electrical signal of a level, which corresponds to thecomposition result of the spectral characteristics of plural colorfilters disposed at different positions on a plane in the N-dividedpixel units 100 c and 103 c, is output from the N-divided pixel units100 c and 103 c. That is, with the N-divided pixel units 100 c and 103 cof a configuration of the present technology, a new spectralcharacteristic, which is different from the spectral characteristics ofthe original materials for the A-color filter and the B-color filter,can be created.

Same as the N-divided pixel units 100 c and 103 c of a configuration ofthe present technology to which the first adding technique is applied,it is assumed that, in the N-divided pixel units 100 c and 103 c of aconfiguration of the present technology to which the second addingtechnique is applied, the filters are replaced with, for example, aD-color filter and an E-color filter each having a characteristic shownin FIG. 12.

In this case also, in the N-divided pixel units 100 c and 103 c of aconfiguration of the present technology to which the second addingtechnique is applied, the electrical signals each having a levelcorresponding to the spectral characteristic of the D-color filter orthe E-color filter may be read at different or same timing, and thenadded by unshown image signal reading section. With this, electricalsignals of the same number as the types of the color filters; i.e., inthis case, two different electrical signals can be obtained.

The image signal reading section at the downstream (for example, theimage signal reading section 533 shown in FIG. 20, which will bedescribed below) may be configure as below. That is, before adding theelectrical signals each having a different level, plural gains differentfrom each other are set for the lights each having an identical spectralcharacteristic; and after reading the electrical signals at different orsame timing, the electrical signals each having a level amplified by therespective gains are added. With this also, a new spectralcharacteristic can be created by the N-divided pixel units 100 c and 103c of a configuration of the present technology to which the secondadding technique is applied. By electrically combining the spectralcharacteristics of plural color filters as described above, the spectralcharacteristics can be optimally controlled to be suitable for thepurpose of application.

In the N-divided pixel unit of a configuration of the present technologywhich has been described referring to figures at the right side in FIG.11 and in FIG. 13, the electrical signals from the N photodiodes areoutput after all of the signals are added; or added after all of thesignals are output. However, in the N-divided pixel unit of aconfiguration of the present technology, each of the electrical signalsfrom the N photodiodes may be separately output without being added, andmay be directly used as one electrical signal by the image signalreading section at the downstream (for example, the image processingsection 515 shown in FIG. 20, which will be described below).

For example, in the calculation in a linear matrix, the larger number oftypes of electrical signals corresponding to the colors is available forthe calculation, the higher color reproducibility of output image isobtained. Therefore, there is known a technique in which, in order toenhance the color reproducibility, for example, a part of greenphotodiodes is replaced with emerald photodiodes to thereby increase thetypes of electrical signals corresponding to the colors available forcalculation. However, when a part of the green photodiodes is replacedwith emerald photodiodes, the resolution may deteriorate due toreduction of the number of the green photodiodes.

Contrarily to this, in the N-divided pixel unit of a configuration ofthe present technology, when an emerald photodiode is used, a greenphotodiode and an emerald photodiode are disposed within a one pixelunit. As a result, both of the number and the resolution of greenphotodiodes are ensured.

Thus, in the N-divided pixel unit of a configuration of the presenttechnology, each of the electrical signals from the N photodiodes can beused separately for signal processing. Therefore, the number ofelectrical signals corresponding to the colors available for signalprocessing can be increased. Accordingly, the color reproducibility canbe enhanced while ensuring the resolution.

As described above, in the N-divided pixel unit of a configuration ofthe present technology, three techniques are available as the techniquesfor outputting the level of the electrical signal from each of the Nphotodiodes. In the first technique, levels of the electrical signalsfrom each of the N photodiodes are directly summed, and then anelectrical signal of a summed level is output. In the second technique,each level of the electrical signals from each of the N photodiodes isamplified by individually preset gain and summed; and then an electricalsignal of a summed level is output. In the third technique, each of theelectrical signals from the N photodiodes is separately output. Byselectively applying these three output techniques, plural differentoutputs can be obtained.

Using these techniques, outputs of electrical signals can be controlledto switch among three outputting mode; i.e., transmission timing fromthe transfer gate and/or individual FD; addition ON/OFF of electricalsignals; and the image signal reading section at the downstream (forexample, the control section 514 shown in FIG. 20, which will bedescribed below). Therefore, by performing above controls, even the sameimage sensor, outputs of different spectral characteristics suitable forwith the purpose of application (for example, a standard camera, amedical device etc), or circumstances (for example, color temperature,illuminance etc) can be obtained.

[Application of Wide Dynamic Range]

In the N-divided pixel unit of a configuration of the presenttechnology, by changing the accumulating time of the light (charge) foreach small pixel as shown in FIG. 14, the wide dynamic range can beapplied.

FIG. 14 illustrates an N-divided pixel unit of a configuration of thepresent technology in which the accumulating time of charge for eachsmall pixel is changed.

FIG. 14 is a top view of a group of the N-divided pixel units 100 b and103 b of a configuration of the present technology and the N-dividedpixel units 101 b and 102 b of a general configuration to which thefirst adding technique is applied. Since the description of the abovehas been made while referring to FIG. 11 etc, the description thereofwill be omitted here.

In the N-divided pixel units 100 b to 103 b at the left side in FIG. 14,the accumulating time of charge in the small pixels is the same.

Contrarily, in the N-divided pixel units 100 b to 103 b at the rightside in FIG. 14, the accumulating time of charge for each small pixel ischanged.

In particular, the A-color filters 112 b-UL and B-color filter 112 b-URdisposed in the N-divided pixel unit 100 b of a configuration of thepresent technology are adapted to a long period accumulation(hereinafter, referred to as long accumulation). Contrarily, the A-colorfilters 112 b-DL and the B-color filter 112 b-DR disposed in theN-divided pixel unit 100 b of a configuration of the present technologyare adapted to short period accumulation (hereinafter, referred to asshort accumulation).

In the N-divided pixel unit 101 b of a general configuration also, theblue color filters 115 b-UL and 115 b-UR are adapted to longaccumulation; the blue color filters 115 b-DL and 115 b-DR are adaptedto short accumulation.

In the N-divided pixel unit 102 b of a general configuration also, theblue color filters 116 b-UL and 116 b-UR are adapted to longaccumulation; the blue color filters 116 b-DL and 116 b-DR are adaptedto short accumulation.

The B-color filter 117 b-UL and the A-color filter 117 b-UR disposed inthe N-divided pixel unit 103 b of a configuration of the presenttechnology are adapted to long accumulation; the A-color filter 117 b-DLand the B-color filter 117 b-DR are adapted to short accumulation.

In this case, in the N-divided pixel units 100 b to 103 b, both of theA-color filter and the B-color filter are disposed in each of the smallpixels of long accumulation and each of the small pixels of shortaccumulation. Therefore, in the N-divided pixel units 100 b to 103 b, inboth of the small pixel of long accumulation and the small pixel ofshort accumulation, an output which has a new spectral characteristic isobtained as a composition result of the spectral characteristics of theA-color filter and the B-color filter. That is, with the N-divided pixelunit of a configuration of the present technology, an output of a newspectral characteristic can be obtained by applying the wide dynamicrange.

[Example Color Filters Disposed in Pixel Unit]

In the above-described example, in a pixel unit of a configuration ofthe present technology, the green color filter is replaced with pluralcolor filters (i.e., A-color filter and B-color filter). However, othercolor filter, for example, a red color filter or a blue color filter maybe replaced with plural color filters. In the pixel unit of aconfiguration of the present technology, a color filter of a pigmentmaterial or a dye material may be disposed. The pixel unit of aconfiguration of the present technology is applicable to pixels whichare disposed in bayer array, clear bit array, or other array.

In the above example, in the pixel unit of a configuration of thepresent technology, a green color filter is divided into four, andreplaced with plural color filters of a number 1:1 ratio (i.e., twoA-color filters and two B-color filters) respectively. However, thenumber of divisions (i.e. number of small pixels) and the ratio ofnumber of plural color filters are not limited to the above.

In the above example, in the pixel unit of a configuration of thepresent technology, the A-color filter and the B-color filter aredisposed with a ratio of 1:1(i.e., two each). Therefore, the lightoutput from the pixel unit of a configuration of the present technologyhas a spectral characteristic of an intermediate characteristic betweenthe characteristics of the A-color filter and the B-color filter as acomposition result of characteristics of the A-color filter and theB-color filter same as the spectroscopic output C in FIG. 5. Contrarily,when the A-color filter and the B-color filter are disposed with a ratioof 3:1 for example, the light output from the pixel unit of aconfiguration of the present technology has a characteristic closer tothe spectral characteristic of the A-color filter shown in FIG. 5 as acomposition result of the characteristics of the A-color filter and theB-color filter.

In the pixel unit of a configuration of the present technology, maximumnumber of the color filters disposable in one pixel unit is equal to thedivision number of the pixel units; i.e., equal to the number of smallpixels. Referring to FIG. 15, a description will be made on theN-divided pixel unit of a configuration of the present technology inwhich three color filters are disposed.

FIG. 15 is a top view of a group of N-divided pixel units 100 d and 103d of a configuration of the present technology in which three colorfilters are disposed and the N-divided pixel units 101 d and 102 d of ageneral configuration.

In the N-divided pixel unit 100 d of a configuration of the presenttechnology, an A-color filter 112 d-UL, B-color filters 112 d-UR and 112d-DL and a C-color filter 112 d-DR are disposed. That is, in theN-divided pixel unit 100 d of a configuration of the present technology,the A-color filter, the B-color filters and the C-color filter aredisposed with the ratio of 1:2:1 in number.

Likewise, in the N-divided pixel unit 103 d of a configuration of thepresent technology, an A-color filter 117 d-UL, B-color filters 117 d-URand 117 d-DL and a C-color filter 117 d-DR are disposed. That is, in theN-divided pixel unit 103 d of a configuration of the present technology,the A-color filter, the B-color filters and the C-color filter aredisposed with the ratio of 1:2:1 in number. The C-color filter is afilter which transmits the light of the wavelength band of the C-colorwhich is different from the wavelength bands of the wavelength bands ofA-color and B-color.

In the N-divided pixel unit 101 d of a general configuration, a bluecolor filter 115 d is disposed. In the N-divided pixel unit 102 d of ageneral configuration, a red color filter 116 d is disposed.

In the N-divided pixel units 100 d and 103 d of a configuration of thepresent technology as described above, the spectral characteristic ofthe light output from the photodiode is a composition result of thespectral characteristics of the A-color filter, the B-color filter andthe C-color filter as shown in FIG. 16.

FIG. 16 is a diagram showing spectral characteristics of the lightsoutput from the photodiodes in the N-divided pixel units 100 d and 103 dof a configuration of the present technology. In FIG. 16, the verticalaxis represents the transmissivity; and the horizontal axis representsthe wavelength.

As shown in FIG. 16, the A-color filter disposed in the N-divided pixelunits 100 d and 103 d of a configuration of the present technology hassuch characteristic that the transmissivity is the highest in a range ofwavelength of 550 nm as indicated with a solid line. The B-color filterdisposed in the N-divided pixel units 100 d and 103 d of a configurationof the present technology has such characteristic that thetransmissivity is the highest in a range of wavelength of 510 nm asindicated with a dotted line. The C-color filter disposed in theN-divided pixel units 100 d and 103 d of a configuration of the presenttechnology has such characteristic that the transmissivity is thehighest in a range of wavelength of 530 nm as indicated with a chainline.

In this case, the spectral characteristic of the light which enters thephotodiode disposed in the N-divided pixel units 100 d and 103 d of aconfiguration of the present technology is a composition result of thecharacteristics of the A-color filter, the B-color filter and C-colorfilter; i.e., a characteristic of spectroscopic output G indicated witha dotted line in FIG. 16. Therefore, in the N-divided pixel units 100 dand 103 d of a configuration of the present technology, an electricalsignal of a level corresponding to the spectroscopic output G is outputfrom the photodiode.

The disposition of the color filters shown in FIG. 15 can be appliedlikely also in the single pixel unit of a configuration of the presenttechnology. In this case, in the single pixel unit of a configuration ofthe present technology, the spectral characteristic of the light outputfrom the photodiode is, same as FIG. 16, the characteristic ofspectroscopic output G. Therefore, in the single pixel unit of aconfiguration of the present technology also, an electrical signal of alevel corresponding to the spectroscopic output G is output from thephotodiode.

As described above, with the pixel unit of a configuration of thepresent technology, by changing the number and type of the disposedplural color filters, a new spectral characteristic can be created.

The combination of the plural color filters disposed in the pixel unitof a configuration of the present technology is not limited to the greencolor filter, the red color filter and blue color filter; but colorfilters which transmit the light of an arbitrary wavelength band may becombined. For example, a white-color filter which transmits the lightsin every wavelength bands may be combined. As for the white-colorfilter, for example, Japanese Unexamined Patent Application PublicationNo. 2009-296276 teaches a white-color filter.

The pixel unit of a configuration of the present technology may bedisposed with a color filter which transmits, for example, infraredlight or ultraviolet light. Referring to FIG. 17, a description will bemade on an N-divided pixel unit of a configuration of the presenttechnology in which color filter which transmits infrared light isdisposed below.

[N-Divided Pixel Unit of a Configuration of the Present TechnologyDisposed with an Infrared Color Filter]

FIG. 17 illustrates an example of a configuration of an N-divided pixelunit of a configuration of the present technology disposed with aninfrared color filter.

Upper figure in FIG. 17 is a top view of a group of N-divided pixelunits 250, 252 and 253 of a configuration of the present technology andan N-divided pixel unit 251 of a general configuration.

In the N-divided pixel unit 250 of a configuration of the presenttechnology, a red color filter is replaced with an I-color filter and aJ-color filter. That is, in the N-divided pixel unit 250 of aconfiguration of the present technology, I-color filters 262-UL and262-DR, and J-color filters 262-UR and 262-DL are disposed. Each of thefour color filters is provided with the transfer gate 210. Also, in acentral portion of the four color filters, the common FD section 211 isdisposed.

Here, referring to FIG. 18, a description is made on the spectralcharacteristics of the I-color filter and the J-color filter.

FIG. 18 is a diagram showing the spectral characteristics of the I-colorfilter and the J-color filter. In FIG. 18, the vertical axis representsthe transmissivity; and the horizontal axis represents the wavelength.

The I-color filter has such characteristic that the transmissivity isthe highest at a wavelength of around 600 nm as indicated with a solidline. The J-color filter has such characteristic that the transmissivityis the highest at a wavelength of around 800 nm as indicated with asolid line. As described above, the I-color filter and the J-colorfilter are color filters that transmit the lights within a wavelengthband (about 700 to 1000 nm) in which a general infrared color filtertransmits the lights.

Returning to FIG. 17, in the N-divided pixel unit 251 of a generalconfiguration, four blue color filters 265-UL, 265-UR, 265-DL and 265-DRare disposed. Each of the four blue color filters is provided with thetransfer gate 210. In a central portion of the four blue color filters,the common FD section 211 is disposed.

In the N-divided pixel unit 252 of a configuration of the presenttechnology, the green color filter is replaced with the A-color filterand the B-color filter. In the N-divided pixel unit 252 of aconfiguration of the present technology, A-color filters 266-UL and266-DR, and B-color filters 266-UR and 266-DL are disposed. Each of thefour color filters is provided with the transfer gate 210. Also, in acentral portion of the four color filters, the common FD section 211 isdisposed.

In the N-divided pixel unit 253 of a configuration of the presenttechnology, J-color filters 267-UL and 267 b-DR, and I-color filters267-UR and 267-DL are disposed. Each of the four color filters isprovided with the transfer gate 210. Also, in a central portion of thefour color filters, the common FD section 211 is disposed.

The example in FIG. 17 shows the N-divided pixel units 250 and 252 inwhich the red color filter is replaced with the I-color filter and theJ-color filter, and the N-divided pixel unit 252 in which the greencolor filter is replaced with the A-color filter and the B-color filter.Like this, with respect to plural types of pixel units, plural colorfilters may be disposed.

Figures at the lower-left and at the lower-right in FIG. 17 are across-sectional view respectively taken along a line L-L′ on theN-divided pixel unit 252 and N-divided pixel unit 253 of a configurationof the present technology.

As shown at the lower-left in FIG. 17, electrical signals of differentlevels each corresponding to the amount of the received light at theA-color filters 266-UL and 266-DR, and the B-color filters 266-UR and266-DL in the N-divided pixel unit 252 of a configuration of the presenttechnology are transferred to the transfer gate 210 respectively, andthen transferred to the common FD section 211. All electrical signalsare added in the common FD section 211 and output therefrom.

Also, as shown at the lower-right in FIG. 17, electrical signals ofdifferent levels each corresponding to the amount of the received lightat J-color filters 267-UL and 267-DR, and the I-color filters 267-UR and267-DL in the N-divided pixel unit 253 of a configuration of the presenttechnology are transferred to the transfer gate 210 respectively, andthen transferred to the common FD section 211. All electrical signalsare added in the common FD section 211 and output therefrom.

Likewise, in the N-divided pixel unit 250 of a configuration of thepresent technology and the N-divided pixel unit 251 of generalconfiguration, in the common FD section 211 all electrical signals areadded and a resultant signal is output therefrom.

As described above, in the N-divided pixel units 250, 252 and 253 of aconfiguration of the present technology, and the N-divided pixel unit251 of a general configuration, all of the electrical signals from thephotodiodes are added and then output therefrom. However, as describedabove, each of the electrical signals from the N photodiodes may beseparately output as one electrical signal directly to the image signalreading section at the downstream (for example, the image signal readingsection 533 shown in FIG. 20, which will be described below).

For example, each of the electrical signals from the photodiodes of theN-divided pixel units 250 and 253 of a configuration of the presenttechnology in which two different I-color filter and J-color filter,which transmits infrared light are disposed, may be directly used forsignal processing in the image processing section at the downstream. Inthis case, when a light from a single light source such as a white lightenters the photodiodes of the N-divided pixel units 250 and 253 of aconfiguration of the present technology, two different outputs can beobtained from the infrared light range. Further, in the N-divided pixelunits 250 and 253 of a configuration of the present technology, sinceplural color filters are included in one pixel unit, the resolution isensured.

Therefore, an imaging apparatus mounted with the image sensor configuredincluding the N-divided pixel units 250 and 253 of a configuration ofthe present technology is applicable, for example, to a medical deviceand the like used for analyzing live body information such ashemoglobin.

[Application to Medical Devices]

FIG. 19 illustrates an example of a configuration of a live bodyinformation obtaining system, in which an imaging apparatus including animage sensor constituted of the N-divided pixel unit of a configurationof the present technology is applied.

A live body information obtaining system 300 shown in FIG. 19 is asystem in which an imaging apparatus obtains images of a live bodyutilizing the light passing therethrough to analyze the obtained images.

The live body information obtaining system 300 radiates a ray of light,which is emitted from a single light source provided to a light emittingsection 314 attached to a support section 312 of a base 311, to a partof the live body, for example, a finger 320 which is inserted through aninsertion port 313 as shown in FIG. 19. The live body informationobtaining system 300 takes pictures of the finger 320 as the object witha camera 330 supported by the support section 315 of the base 311. Thecamera 330 includes a lens section 341, a housing 342, and an imageprocessing section 343. The live body information obtaining system 300analyzes the images taken by the camera 330 in the image processingsection 343.

In the housing 342 of the camera 330, an image sensor constituted of anN-divided pixel unit of a configuration of the present technology ismounted. Therefore, even when the pictures of the object are taken usingthe light of a single light source emitted from the light emittingsection 314, the camera 330 can output two different image signals whichare different from each other in the infrared light range. Therefore, byanalyzing the live body information using these outputs, the accuracy ofthe analysis is expected to be enhanced.

For example, the output values in an infrared light range may used forblood tests. That is, oxidation and deoxidation of hemoglobin in a bloodcan be analyzed using the output values in the infrared light range. Atthis time, output values of two sets of different wavelengths in theinfrared light range are used. In known technology (for example,Japanese Patent No. 2932644), two sets of light are radiated to obtainoutput values of two different wavelengths. However, even when a singlecolor light is used, the technique of the present technology is capableof obtaining two or more of output values from the pixel unit. Thus, thetechnique of the present technology is applicable to blood analysis orthe like.

As described above, the technique of the present technology is capableof creating new spectral characteristics, which are difficult to obtainwith the spectral characteristic of materials of color filters.Therefore, in the medical or industrial field for example, even when aspecial spectral characteristic, which is out of the spectralcharacteristic in a visual range of mankind, is needed, the pixel unitof a configuration of the present technology is capable of optimallycontrolling the spectral characteristic to be suitable for the purposeof application. Further, by controlling the spectral characteristic, theS/N ratio and the color reproducibility are enhanced.

Moreover, the technique of the present technology is capable ofoptimally designing a pixel unit suitable for the purpose ofapplication. Therefore, even when, for example, it is difficult todivide the photodiode due to miniaturization of pixel unit, by using thetechnique of the present technology described referring to FIGS. 3, 4and 10 etc, optimal pixel unit can be designed suitably for the purposeof application. Also, for example, for increasing the degree of freedomof application by setting the gain and signal processing, optimal pixelunit suitable for the purpose of application can be designed by usingthe technique of the present technology described referring to FIG. 11or later.

Moreover, since the technique of the present technology increases thedegree of freedom and controllability of the spectral characteristics,the light source can be easily estimated. That is, the technique of thepresent technology is capable of creating new spectral characteristicsusable for estimating the light source in addition to the spectralcharacteristics of pixel values of R-pixel, G-pixel and B-pixel.Accordingly, a new light source such as white LED can be easilyestimated.

[Imaging Apparatus]

FIG. 20 is a block diagram showing an example of a configuration of animaging apparatus on which an image sensor which is configured includingthe above-described pixel unit of a configuration of the presenttechnology; i.e., an imaging apparatus to which the present technologyis applied.

As shown in FIG. 20, an imaging apparatus 500 includes a lens section511, an image sensor 512, an operation section 513, a control section514, an image processing section 515, a display section 516, a codecprocessing section 517 and a recording section 518.

The lens section 511 adjusts the focus to an object, concentrates thelight from a focused position, and supplies the light to the imagesensor 512.

The image sensor 512 is configured including a filter section 531 and apixel section 532, and an image signal reading section 533.

The filter section 531 and the pixel section 532 constitute a group ofplural pixel units to which the present technology is applied. That is,from view point of the pixel unit, the on-chip lens and the color filterconstitute a part of the filter section 531. The photodiode constitutesa part of the pixel section 532. In other word, a group of the on-chiplens and the color filter included in each pixel unit constitutes thefilter section 531. A group of the photodiodes included in each pixelunit constitutes the pixel section 532.

The pixel section 532 receives the light entering through the lenssection and the filter section 531, and then converts the light intoelectric signal based on the control by the image signal reading section533 and outputs a voltage signal (analog signal) corresponding to theintensity of the light.

That is, the image signal reading section 533 reads the analog signal ofeach pixel unit from the pixel section 532 as the image signal andperforms A/D (Analog/Digital) conversion to obtain digital image signal,and supplies the same to the image processing section 515. Here, whenone pixel unit includes plural small pixels, the image signal readingsection 533 amplifies and/or adds pixel signal from each small pixelbefore or after the A/D conversion upon the necessity to generate pixelsignal of pixel unit.

The operation section 513 is configured including, for example, JogDial(trademark), keys, buttons or touch panel and the like. Receivingoperation inputs made by a user, the operation section 513 suppliessignals to the control section 714 corresponding to the operation input.

The control section 514 controls the lens section 511, the image sensor512, the image processing section 515, the display section 516, thecodec processing section 517 and the recording section 518 based on thesignals corresponding to the operation input made by the user throughthe operation section 513. For example, the control section 514 controlsthe image sensor 512 to switch the output manner of the level ofelectrical signal from each of the N photodiodes in the N-divided pixelunit of a configuration of the present technology.

The image processing section 515 performs signal processing or variousimage processing such as, for example, white balance adjustment,de-mosaic processing, matrix processing, gamma correction and YCconversion on the image signals supplied from the image sensor 512, andsupplies the same to the display section 516 and the codec processingsection 517.

The display section 516 is configured as, for example, a liquid crystaldisplay and displays images of the object based on the image signalsfrom the image processing section 515.

The codec processing section 517 performs a predetermined codingprocessing on the image signals from the image processing section 515and supplies the image data obtained as a result of the codingprocessing to the recording section 518.

The recording section 518 recodes the image data from the codecprocessing section 517. The image data recorded in the recording section518 is read by the image processing section 515 upon the necessity andis supplied to the display section 516, and corresponding image isdisplayed.

The configuration of the imaging apparatus which includes a solidimaging device to which the present technology is applied is not limitedto the above, but another configuration may be employed.

The configuration, which has been described as a one device (orprocessing section) in the above description, may be configuredincluding plural devices (or processing sections). Contrarily, theconfiguration, which has been described as plural devices (or processingsections) in the above description, may be configured as an integrateddevice (or processing section). Needless to say that each of the devices(or processing sections) may be configured including additionalconfiguration other than that described above. When the configurationand the operation of the entire system are substantially identical, apart of the configuration of a device (or processing section) may beincluded in a configuration of other device (or other processingsection). That is, the embodiment of the present technology is notlimited to the above-described embodiments, but various modificationsare conceivable within a range of the sprit of the present technology.

Additionally, the present technology may also be configured as below.

(1) An image sensor including:

a pixel unit,

the pixel unit including

a photodiode,

a first color filter and a second color filter each disposed in adifferent position on a plane above the photodiode, and

a first on-chip lens disposed over the first color filter and a secondon-chip lens disposed over the second color filter.

(2) The image sensor according to (1), wherein

each of the first color filter and the second color filter has aspectral characteristic different from each other.

(3) The image sensor according to (1) or (2), wherein

the pixel unit outputs an electrical signal of a level corresponding toa composition result of the spectral characteristics of the first colorfilter and the second color filter.

(4) The image sensor according to any one of (1) to (3), wherein

the photodiode includes a first photodiode disposed below the firstcolor filter and a second photodiode disposed below the second colorfilter, and

electrical signals output from the pixel unit having levelscorresponding to the respective spectral characteristics of the firstcolor filter and the second color filter are added.

(5) The image sensor according to any one of (1) to (4), wherein

the pixel unit further includes a common floating diffusion that addselectrical signals output from each of the first photodiode and thesecond photodiode.

(6) The image sensor according to any one of (1) to (5), wherein

each of the electrical signals output from the first photodiode and thesecond photodiode is amplified by an individually preset gain.

(7) The image sensor according to any one of (1) to (6), wherein

each of the first photodiode and the second photodiode is individuallypreset with a charge accumulating time.

(8) The image sensor according to any one of (1) to (7), wherein

each of the first color filter and the second color filter has acharacteristic to transmit infrared light.

(9) The image sensor according to any one of (1) to (8), wherein

the pixel unit includes

a group of color filters which includes one or more color filters inaddition to the first color filter and the second color filter, and

a group of on-chip lenses which includes one or more on-chip lenses inaddition to the first on-chip lens and the second on-chip lens, the oneor more on-chip lenses being disposed over the one or more color filtersin addition to the first color filter and the second color filter.

(10) The image sensor according to any one of (1) to (9), wherein

the pixel unit outputs an electrical signal of a level corresponding toa composition result of the respective spectral characteristics of thecolor filter group.

(11) The image sensor according to any one of (1) to (10), wherein

the photodiode is constituted of a photodiode group each disposed belowthe color filter group, and

electrical signals output from the pixel unit each having a levelcorresponding to a spectral characteristic of the color filter group areadded.

(12) The image sensor according to any one of (1) to (11), wherein

the pixel unit further includes a common floating diffusion that addsthe electrical signals each output from the photodiode groups.

(13) The image sensor according to any one of (1) to (12), wherein

each of the electrical signals output from the photodiode groups isamplified by an individually preset gain.

(14) The image sensor according to any one of (1) to (13), wherein

each photodiode group is individually preset with a charge accumulatingtime.

(15) The image sensor according to any one of (1) to (14), wherein

each of the color filter groups has a characteristic to transmitinfrared light.

(16) The image sensor according to any one of (1) to (15), wherein

a waveguide is formed above the photodiode.

(17) The image sensor according to any one of (1) to (16), wherein

the photodiode has a plurality of output modes which are selectivelyswitchable through an inner or outer control of the image sensor.

(18) An imaging apparatus mounted with an image sensor including a pixelunit,

the pixel unit including

a photodiode,

a first color filter and a second color filter each disposed in adifferent position on a plane above the photodiode, and

a first on-chip lens disposed over the first color filter and a secondon-chip lens disposed over the second color filter.

(19) A live body imaging apparatus including an imaging apparatusmounted with an image sensor including a pixel unit,

the pixel unit including

a photodiode,

a first color filter and a second color filter each disposed in adifferent position on a plane above the photodiode, and

a first on-chip lens disposed over the first color filter and a secondon-chip lens disposed over the second color filter,

wherein the imaging apparatus takes a picture of a live body as anobject.

The present technology is applicable to an image sensor or an imagingapparatus.

The present disclosure contains subject matter related to that disclosedin Japanese Priority Patent Application JP 2011-183303 filed in theJapan Patent Office on Aug. 25, 2011, the entire content of which ishereby incorporated by reference.

What is claimed is:
 1. An image sensor comprising: a pixel unit; thepixel unit including: a first on-chip lens disposed over the first colorfilter and a second on-chip lens disposed over the second color filter,wherein a spectral response of the first color filter is different thana spectral response of the second color filter, and wherein anelectrical signal output from the pixel unit is a result of acombination of spectral characteristics of the first and second colorfilters.
 2. The image sensor according to claim 1, wherein the pixelunit outputs an electrical signal of a level corresponding to acomposition result of the spectral characteristics of the first colorfilter and the second color filter.
 3. The image sensor according toclaim 1, wherein: the photodiode includes a first photodiode disposedbelow the first color filter and a second photodiode disposed below thesecond color filter, and electrical signals output from the pixel unithaving levels corresponding to the respective spectral characteristicsof the first color filter and the second color filter are added.
 4. Theimage sensor according to claim 3, wherein the pixel unit furtherincludes a common floating diffusion that adds electrical signals outputfrom each of the first photodiode and the second photodiode.
 5. Theimage sensor according to claim 3, wherein each of the electricalsignals output from the first photodiode and the second photodiode isamplified by an individually preset gain.
 6. The image sensor accordingto claim 3, wherein each of the first photodiode and the secondphotodiode is individually preset with a charge accumulating time. 7.The image sensor according to claim 1, wherein each of the first colorfilter and the second color filter has a characteristic to transmitinfrared light.
 8. The image sensor according to claim 1, wherein thepixel unit includes: a group of color filters which includes one or morecolor filters in addition to the first color filter and the second colorfilter, and a group of on-chip lenses which includes one or more on-chiplenses in addition to the first on-chip lens and the second on-chiplens, the one or more on-chip lenses being disposed over the one or morecolor filters in addition to the first color filter and the second colorfilter.
 9. The image sensor according to claim 8, wherein the pixel unitoutputs an electrical signal of a level corresponding to a compositionresult of the respective spectral characteristics of the color filtergroup.
 10. The image sensor according to claim 9, wherein each of thecolor filter groups has a characteristic to transmit infrared light. 11.The image sensor according to claim 8, wherein: the photodiode isconstituted of a photodiode group each disposed below the color filtergroup, and electrical signals output from the pixel unit each having alevel corresponding to a spectral characteristic of the color filtergroup are added.
 12. The image sensor according to claim 11, wherein thepixel unit further includes a common floating diffusion that adds theelectrical signals each output from the photodiode groups.
 13. The imagesensor according to claim 11, wherein each of the electrical signalsoutput from the photodiode groups is amplified by an individually presetgain.
 14. The image sensor according to claim 11 wherein each photodiodegroup is individually preset with a charge accumulating time.
 15. Theimage sensor according to claim 1, wherein a waveguide is formed abovethe photodiode.
 16. The image sensor according to claim 1, wherein thephotodiode has a plurality of output modes which are selectivelyswitchable through an inner or outer control of the image sensor. 17.The image sensor of claim 1, further comprising: a plurality of pixelunits, wherein a first portion of the plurality of pixel units include asingle photodiode and first and second color filters, and wherein asecond portion of the plurality of pixels include a single photodiodeand a single color filter.
 18. An imaging apparatus mounted with animage sensor comprising a pixel unit, the pixel unit including: at leasta first photodiode; a first color filter and a second color filter eachdisposed in a different position on a plane above the at least a firstphotodiode; a first on-chip lens disposed over the first color filterand a second on-chip lens disposed over the second color filter, whereina spectral response of the first color filter is different than aspectral response of the second color filter, and wherein an electricalsignal output from the pixel unit is a result of a combination ofspectral characteristics of the first and second color filters.
 19. Alive body imaging apparatus including an imaging apparatus mounted withan image sensor comprising a pixel unit, the pixel unit including: atleast a first photodiode; a first color filter and a second color filtereach disposed in a different position on a plane above the at least afirst photodiode; and a first on-chip lens disposed over the first colorfilter and a second on-chip lens disposed over the second color filter,wherein a spectral response of the first color filter is different thana spectral response of the second color filter, and wherein anelectrical signal output from the pixel unit is a result of acombination of spectral characteristics of the first and second colorfilters, wherein, the imaging apparatus takes a picture of a live bodyas an object.